In a digital signal processing application, different techniques may be utilized to convert from one sampling rate to another sampling rate. For example, a digital signal sampled at a first rate may be converted into an analog signal using a digital-to-analog converter (DAC), and the analog signal may then be sampled at a second rate using an analog-to-digital converter (ADC). However, this conversion may be costly and may create distortion that degrades the quality of the resulting signal to a degree that renders the method unusable for some applications.
Another sampling rate conversion technique may interpolate and decimate a digital signal. The digital signal may be interpolated from a first rate to a multiple of the first rate. Decimation may then be applied to produce a second rate. U.S. Pat. No. 6,870,492, entitled Method of Near-unity Fractional Sampling Rate Alteration for High Fidelity Digital Audio, provides a method of efficiently converting the sampling rate of a digital signal from a first sampling rate to a second sampling rate that is only slightly different than the first sampling rate.
A digital system may comprise multiple clock domains generated by independent oscillators. Oscillators may vary with time, temperature, and age, and if this variation causes sampling rates to drift with respect to each other, the drift may alter further processing such as circuits that rely directly or indirectly on the oscillator clock. A sample rate conversion that is based on a fixed ratio between the sample rates may fail to track this type of change.
Limitations and disadvantages of conventional and traditional approaches will become apparent to one of ordinary skill in the art through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.